Yevgeny Roizman announces resignation, criticising the abolition of direct elections as a blow to democracy.

Yevgeny Roizman, the mayor of Russia's fourth-largest city and a rare critic of the Kremlin in a senior region position, has quit to protest against a government-promoted law which scrapped mayoral elections.

Lawmakers voted last month to abolish direct mayoral elections in Yekaterinburg, located more than 1,500km east of the capital, Moscow. Mayors will now be elected by the legislature from a shortlist drawn up by a special commission.

"I don't want [to] be part of this and I am resigning," Roizman told lawmakers on Tuesday in the local legislature.

A charismatic opposition politician who narrowly beat a Kremlin-backed candidate in the mayoral race in 2013, Roizman had been due as chairman of the legislature to put the scrapping of elections to lawmakers for a final vote.

Instead, he told lawmakers he refused to "legitimise someone else's decision" and pronounced the session closed, video of his speech shared online showed.

Speaking to Radio Free Europe/Radio Liberty (RFE/RL), Roizman described the amendments as "a direct cheat on the people of [the city]".

"This is Yekaterinburg - people will understand me. It was the only way to come clean out of this situation," he added. "Step by step, the local council is being stripped of everything - authority, finance, direct elections."

According to RFE/RL, Roizman's position is already largely ceremonial, as most executive powers in Yekaterinburg belong to the head of the city administration, Aleksandr Yakob.

'Remain in history'

Critics say Russian President Vladimir Putin has tightened his control over electoral politics over the nearly two decades that he has spent as president or prime minister.

Roizman is one of the few leading Russian regional officials who openly criticises Putin, who was re-elected president in March in a landslide victory, and supports his archrival Alexey Navalny.

As mayor, Roizman has regularly attended demonstrations organised by Navalny who was barred from running the March vote.

Roizman had called for a boycott of the presidential vote, saying the election was not free or fair.

Leonid Volkov, an opposition politician from Yekaterinburg, said Roizman's resignation had obstructed the passage of the election legislation, but that it was unlikely to stop direct elections being scrapped eventually.

"This political act and civic deed will, however, remain in history," Volkov wrote on social media.